1. Technical Field
The present invention relates to a method for correcting distortion of an image projected by a projector, and a projector.
2. Related Art
Currently, a projector which modulates light emitted from a light source according to inputted image signals to form projection images is known, and used for presentation and home theater.
Images projected by the projector are generally formed on a screen. This screen looks flat, but is not completely flat but actually has concaves and convexes. A certain portable winding-type screen or the like has large concaves and convexes. When images are projected on this type of screen, distortion is caused on the images in some cases.
For example, when the projector is disposed immediately below the screen for image projection, images are projected on the screen from below toward above. Thus, projection images are considerably distorted in the up-down direction.
For eliminating this distortion, JP-A-11-146307 discloses a technology for converting distorted images on a screen into appropriate images by correcting picture images displayed on a display panel.
Also, JP-A-2001-83949 discloses a technology for capturing images of projection images formed on a screen having freely curved surface by using a camera disposed at a viewpoint, producing correction data for giving opposite distortion beforehand, and correcting picture images desired to be projected based on the correction data.
According to the technology shown in JP-A-11-146307, distortion of relative positions between the screen and the projector can be corrected. However, distortion produced on the screen due to the concaves and convexes of the screen cannot be corrected.
According to the technology shown in JP-A-2001-83949, in case of images having partial large distortion, correction patterns for obtaining detailed information about the entire areas of the images are required for correcting images with high accuracy. In this case, processing load increases.